Surgical instrument and method of disassembling a tibial prosthesis

ABSTRACT

An orthopaedic surgical instrument includes an anchor configured to be coupled to a prosthetic tibial component, a shaft coupled to the anchor, and a separator coupled to the shaft. The separator is configured to move along the shaft between a first position in which the separator is spaced apart from the prosthetic tibial component and a second position in which the separator is positioned between the tibial tray and the sleeve of the prosthetic tibial component.

TECHNICAL FIELD

The present disclosure relates generally to orthopaedic surgicalinstruments and, more particularly, to surgical instruments used in theassembly and disassembly of orthopaedic prosthetic components.

BACKGROUND

Joint arthroplasty is a well-known surgical procedure by which adiseased and/or damaged natural joint is replaced by a prosthetic joint.For example, in a total knee arthroplasty surgical procedure, apatient's natural knee joint is partially or totally replaced by aprosthetic knee joint or knee prosthesis. A typical knee prosthesisincludes a tibial component, a femoral component, and an insert orbearing component positioned between the tibial component and thefemoral component. The tibial component generally includes a platform orplate having a stem extending distally therefrom, and the femoralcomponent generally includes a pair of spaced apart condylar elements,which include surfaces that articulate with corresponding surfaces ofthe polymer bearing. The stem of the tibial tray is configured to beimplanted in a surgically-prepared medullary canal of the patient'stibia, and the femoral component is configured to be coupled to asurgically-prepared distal end of a patient's femur

From time to time, a revision knee surgery may need to be performed on apatient. In such a revision knee surgery, the previously-implanted kneeprosthesis is surgically removed and a replacement knee prosthesis isimplanted. In some revision knee surgeries, all of the components of thepreviously-implanted knee prosthesis, including, for example, the tibialcomponent, the femoral component, and the polymer bearing component, maybe surgically removed. In other revision knee surgeries, only part ofthe previously-implanted knee prosthesis may be removed and replaced.

During a revision knee surgery, the orthopaedic surgeon typically uses avariety of different orthopaedic surgical instruments such as, forexample, cutting blocks, surgical reamers, drill guides, prosthetictrials, and other surgical instruments to prepare the patient's bones toreceive the knee prosthesis.

SUMMARY

According to one aspect of the disclosure, an orthopaedic surgicalinstrument is disclosed. The orthopaedic surgical instrument includes ananchor having a longitudinal axis, and a shaft coupled to the anchor.The shaft has a longitudinal axis extending orthogonal to thelongitudinal axis of the anchor. The orthopaedic surgical instrumentalso includes a separator coupled to the shaft. The separator has a pairof arms and a slot defined therebetween. The separator is configured tomove along the longitudinal axis of the shaft between a first positionin which the anchor is spaced apart from the slot of the separator and asecond position in which the anchor is received in the slot definedbetween the pair of arms.

In some embodiments, each arm of the separator may include a topsurface, a bottom surface, and a tapered surface extending between thetop surface and the bottom surface. Additionally, in some embodiments,the separator may include a body secured to the pair of arms, and theshaft may be positioned in a bore defined in the body.

In some embodiments, the orthopaedic surgical instrument may include acollar rotatively coupled to the shaft, and the collar may be operableto move the separator between the first position and the secondposition. Additionally, in some embodiments, the shaft may have aplurality of external threads formed thereon, and the bore in the bodymay be defined by a substantially smooth inner surface that engages theshaft. In some embodiments, the collar may include an opening defined ina first end thereof and an inner wall that extends inwardly from theopening, and the inner wall of the collar may have a plurality ofinternal threads formed thereon. The plurality of internal threads maybe engaged with a number of the external threads of the shaft.

In some embodiments, the first end of the collar may be engaged with thebody such that rotation of the collar in a first direction causes theseparator to advance between the first position and the second position.In some embodiments, the body may be positioned between the anchor andthe collar.

Additionally, in some embodiments, the orthopaedic surgical instrumentmay include a handle configured to rotate the collar about thelongitudinal axis of the shaft to advance the separator between thefirst position and the second position. The handle may have a socketdefined therein. The collar may have a shank sized to be positioned inthe socket defined in the handle.

In some embodiments, the anchor may include a cylindrical shaftextending along the longitudinal axis of the anchor. The cylindricalshaft may be sized and shaped to be positioned in a bore defined in atibial tray. In some embodiments, the orthopaedic surgical instrumentmay include a stabilizer including a rod received in a bore defined inthe anchor.

According to another aspect, an orthopaedic surgical instrument includesan anchor including a frustoconical first body and a cylindrical secondbody extending downwardly from the frustoconical first body, and a shaftsecured to the anchor. The shaft has an externally-threaded outersurface and a longitudinal axis. The orthopaedic surgical instrumentincludes a housing having an internally-threaded inner surface engagedwith externally-threaded outer surface of the shaft, and the housing isconfigured to rotate about the longitudinal axis of the shaft. Theorthopaedic surgical instrument also includes a separator including amounting body positioned between the anchor and the housing and a pairof arms having a slot defined therebetween. The housing is engaged withthe mounting body such that rotation of the housing about thelongitudinal axis causes the separator to move between a first positionin which the anchor is spaced apart from the slot of the separator and asecond position in which the anchor is received in the slot definedbetween the pair of arms.

In some embodiments, each arm of the separator may include a taperedsurface. In some embodiments, the anchor may include a base secured tothe shaft, and the first body may be secured to a lower end of the base.

According to another aspect, a method of performing an orthopaedicsurgical procedure is disclosed. The method includes securing an anchorto a tibial prosthetic component implanted in a proximal end of apatient's tibia. The tibial prosthetic component includes a tibial trayand a tibial sleeve secured to the tibial tray. The method also includesmoving a separator posteriorly toward the anchor to position a tip ofthe separator between a lower side of the tibial tray and an upper endof the tibial sleeve, advancing the separator from anterior to posteriorbetween the lower side of the tibial tray and the upper end of thetibial sleeve to detach the tibial tray from the tibial sleeve, andremoving the tibial tray from the proximal end of the patient's tibia.

In some embodiments, the method may further include positioning acylindrical body of the anchor in an opening defined in the tibial tray.Additionally, in some embodiments, moving the separator toward theanchor includes sliding the separator along a shaft secured to theanchor.

In some embodiments, a collar may be threaded onto the shaft. In someembodiments, sliding the separator along the shaft may include rotatingthe collar on the shaft to advance the collar along the shaft andengaging the separator with the collar as the collar is advanced alongthe shaft.

In some embodiments, the method may include engaging the collar with ahandle, and operating the handle to rotate the collar on the shaft.

In some embodiments, advancing the separator may include positioning awedge of the separator between the tibial tray and the tibial sleeve.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description particularly refers to the following figures,in which:

FIG. 1 is a perspective view of a prosthetic tibial component of a kneeprosthesis;

FIG. 2 is an exploded perspective view of the tibial component of FIG.1;

FIG. 3 is a perspective view of one embodiment of an orthopaedicsurgical instrument for use in disassembling the tibial component ofFIG. 1;

FIG. 4 is a partial cross-section, elevation view of the orthopaedicsurgical instrument of FIG. 3;

FIG. 5 is a perspective view of the tibial component of FIG. 1 implantedin a proximal end of a tibia of a patient;

FIG. 6 is an elevation view of the orthopaedic surgical instrument ofFIG. 3 attached to the implanted tibial component with a separator ofthe orthopaedic surgical instrument spaced apart from the implantedtibial component;

FIG. 7 is a perspective view similar to FIG. 5 showing the separator ofthe orthopaedic surgical instrument engaged with the implanted tibialcomponent;

FIG. 8 is an elevation view similar to FIG. 6 showing the separator inthe position of FIG. 7; and

FIG. 9 a perspective view of another embodiment of an orthopaedicsurgical instrument for use in disassembling the tibial component ofFIG. 1.

DETAILED DESCRIPTION OF THE DRAWINGS

While the concepts of the present disclosure are susceptible to variousmodifications and alternative forms, specific exemplary embodimentsthereof have been shown by way of example in the drawings and willherein be described in detail. It should be understood, however, thatthere is no intent to limit the concepts of the present disclosure tothe particular forms disclosed, but on the contrary, the intention is tocover all modifications, equivalents, and alternatives falling withinthe spirit and scope of the invention as defined by the appended claims.

Terms representing anatomical references, such as anterior, posterior,medial, lateral, superior, inferior, etcetera, may be used throughoutthe specification in reference to the orthopaedic implants and surgicalinstruments described herein as well as in reference to the patient'snatural anatomy. Such terms have well-understood meanings in both thestudy of anatomy and the field of orthopaedics. Use of such anatomicalreference terms in the written description and claims is intended to beconsistent with their well-understood meanings unless noted otherwise.

Referring now to FIGS. 1-4, a knee prosthesis 10 and a surgicalinstrument 12 are shown. As shown in FIGS. 1 and 2, the knee prosthesis10 includes a prosthetic tibial component 14 that is configured to beimplanted in a surgically-prepared proximal end 16 of a patient's tibia18 (see FIG. 5). As described in greater detail below in reference toFIGS. 5-8, the surgical instrument 12 may be used in a joint replacementprocedure to remove the tibial component 14 from the patient's tibia 18.It should be appreciated that although the surgical instrument 12 isherein described in regard to the performance of a total kneereplacement procedure, certain of the concepts associated with theinstrument 12 may be utilized in association with replacement proceduresat numerous other joint locations throughout the body.

As shown in FIG. 1, the tibial component 14 of the knee prosthesis 10includes a tibial tray 20 and a sleeve 22. The tibial tray 20 isconfigured to be coupled to a tibial bearing component (not shown) ofthe knee prosthesis 10. The tibial tray 20 includes a platform 24 and afixation member, such as an elongated stem 26, extending away from adistal side 28 of the platform 24. An opening 30 is defined in aproximal surface 32 of the platform 24, and the tibial tray 20 includesan inner wall 34 that extends distally from the opening 30. The innerwall 34 defines a bore 36 extending through the platform 24 into thestem 26. The bore 36 is sized and shaped to receive a stem (not shown)of the tibial bearing component of the knee prosthesis 10.

The inner wall 34 of the tibial tray 20 has a tapered surface 38 thatextends distally from the opening 30 in the proximal surface 32 to adistal edge 40. As shown in FIG. 1, the tapered surface 38 defines aproximal section 42 of the bore 36. The inner wall 34 also includes acylindrical surface 44 that is connected to the tapered surface 38 atthe distal edge 40 thereof. The cylindrical surface 44 extends distallyfrom the edge 40 to define a distal section 46 of the bore 36. It shouldbe appreciated that in other embodiments the inner wall 34 may include asingle tapered surface, a single cylindrical surface, or additionalsurfaces to define the bore 36.

As shown in FIG. 2, the elongated stem 26 of the tibial tray 20 has abody 50 extending from a proximal end attached to the platform 24 to adistal end 54. The body 50 is tapered from a widest dimension at theproximal end to a most narrow dimension at the distal end 54. In theillustrative embodiment, the body 50 has a Morse taper. The distal end54 of the stem 26 is configured to be secured to an extension (notshown).

The tibial tray 20 also includes a pair of keels 56 extending from thedistal side 28 of the platform 24. In the illustrative embodiment, eachkeel 56 extends outwardly from the stem 26 and toward the posterior side58 of the platform 24. It should be appreciated that in otherembodiments the keels may have other geometric relationships and thetibial tray 20 may include additional or fewer keels.

As described above, the tibial component 14 also includes a sleeve 22,which is configured to be secured to the tibial tray 20. The sleeve 22has a body 60 that extends from a proximal end 62 to a distal end 64. Asshown in FIG. 2, the body 60 is tapered from a widest dimension at theproximal end 62 to a most narrow dimension at the distal end 64. In theillustrative embodiment, the body 60 has a stepped or terraced outersurface 66 including a plurality of steps 68. The outer surface 66tapers with each step 68 from the proximal end 62 to the distal end 64.

The sleeve 22 has an opening 70 defined in a proximal surface 72 of thebody 60, and an inner wall 74 extends distally from the opening 70 todefine an interior passageway 76. The passageway 76 is sized and shapedto receive the stem 26 of the tibial tray 20 when the sleeve 22 isassembled with the tray 20. The inner wall 74 tapers from a largestdiameter at the proximal surface 72 to a smallest diameter at the distalend 64. In the illustrative embodiment, the inner wall 74 of the sleeve22 has a Morse taper that matches the Morse taper of the stem 26 of thetibial tray 20.

The sleeve 22 also includes a pair of relief slots 80, 82 that extendinwardly from the outer surface 66 of the body 60. As shown in FIG. 2,the slots 80, 82 open into the passageway 76. The slots 80, 82 are sizedto receive the keels 56 when the sleeve 22 is secured to the tibial tray20.

When the sleeve 22 is assembled with the tibial tray 20, the stem 26 ofthe tibial tray 20 is received in the passageway 76 of the sleeve 22,and the keels 56 are positioned in the slots 80, 82. The stem 26 engagesthe inner wall 74 of the sleeve 22, thereby creating a frictional lockbetween the tibial tray 20 and the sleeve 22. The frictional lockprevents relative rotation and longitudinal movement between the tibialtray 20 and the sleeve 22, thereby forming the tibial component 14. Asshown in FIG. 6, a slot 84 is defined between the distal side 28 of thetibial tray 20 and the proximal surface 72 of the sleeve 22.

The tibial tray 20 and the sleeve 22 are formed of materials suitablefor prosthetic components. Such materials include titanium alloys,cobalt chromium alloys, or other metallic alloys. It should beappreciated that in other embodiments other metallic materials may beused.

Referring now to FIGS. 3 and 4, the surgical instrument 12 may be usedin an orthopaedic surgical procedure during the removal of the tibialcomponent 14 from the patient's tibia 18. In the illustrativeembodiment, the surgical instrument 12 is a disassembly instrument 90configured to separate the tibial tray 20 from the sleeve 22 andfacilitate the removal of the tibial component 14. The instrument 90includes an anchor 92 configured to be secured to the tibial tray 20 anda shaft 94 extending outwardly from the anchor 92. The instrument 90also includes a separator tool 96 configured to move relative to theanchor 92 and engage the tibial component 14 to separate the tibial tray20 from the sleeve 22. An actuation collar 98 is attached to the shaft94 and is operable to move the separator tool 96 along the shaft 94, asdescribed in greater detail below. In the illustrative embodiment, thecomponents of the instrument 90 are formed from a metallic material suchas, for example, steel, titanium alloy, cobalt chromium alloy, and soforth. It should be appreciated that in other embodiments the componentsmay be formed from a hard polymeric material.

The anchor 92 of the instrument 90 includes a base 100 and an engagementarm 102 configured to be positioned in the bore 36 defined in the tibialtray 20. In the illustrative embodiment, the engagement arm 102 issecured to the base 100 via a connecting rod 104. As shown in FIGS. 3and 4, the connecting rod 104 extends between a bottom surface 106 ofthe base 100 and an upper surface 108 of the engagement arm 102. Itshould be appreciated that in other embodiments the engagement arm 102may be secured directly to the base 100.

The engagement arm 102 has a longitudinal axis 110 that extends throughan upper body 112 secured to the connecting rod 104 and a lower body 114positioned below the upper body 112. In the illustrative embodiment, theupper body 112 has a frustoconical outer surface 116 shaped to match thetapered surface 38 that defines the proximal section 42 of the bore 36.When the anchor 92 is secured to the tibial tray 20, the upper body 112of the arm 102 is received in the proximal section 42 of the bore 36 ofthe tibial tray 20. Additionally, the lower body 114 of the engagementarm 102 is received in the distal section 46 of the bore 36 when theanchor 92 is secured to the tibial tray 20. Similar to the upper body112, the lower body 114 has a cylindrical outer surface 118 shaped tomatch the cylindrical surface 44 that defines the distal section 46 ofthe bore 36. It should be appreciated that in other embodiments theengagement arm 102 may be detachable from the base 100. In that way, theinstrument 90 may include multiple engagement arms, and each engagementarm may be sized to be used with a different size of tibial tray.

The base 100 of the anchor 92 includes a pair of side surfaces 120 thatextend upwardly from the bottom surface 106. An opening 122 is definedin each side surface 120, and an inner wall 124 extends between theopenings 122 to define a bore 126 through the base 100. As shown in FIG.4, the bore 126 has a longitudinal axis 128 that extends transverse tothe longitudinal axis 110 of the engagement arm 102. The bore 126 issized to receive a stabilizer rod 130 (see FIG. 7), which may be used bythe surgeon to support the instrument 90 on the patient's tibia 18.

The base 100 of the anchor 92 includes another side surface 132 thatextends upwardly from the bottom surface 106 between the side surfaces120. As shown in FIGS. 3 and 4, the shaft 94 of the instrument 90extends outwardly from the side surface 132. In the illustrativeembodiment, the shaft 94 has a longitudinal axis 140 that extendsorthogonal to the longitudinal axis 110 of the engagement arm 102. Theshaft 94 has a cylindrical outer surface 142 that has a plurality ofexternal threads 144 formed thereon.

As described above, the instrument 90 also includes a separator tool 96that is configured to move relative to the anchor 92. The separator tool96 includes a plate 150 and a body 152 extending upwardly from the plate150. As shown in FIGS. 3 and 4, the body 152 of the separator tool 96 ismounted on the shaft 94. The body 152 has a side surface 154 that facesthe side surface 132 of the base 100 and another side surface 156 thatis positioned opposite the side surface 154. Each surface 154, 156 ofthe body 152 has an opening 160 defined therein. A cylindrical innerwall 162 extends between the openings 160 to define a passageway 164through the body 152. As shown in FIG. 4, the shaft 94 extends throughthe passageway 164 of the body 152. The inner wall 162 of the body 152is substantially smooth such that the separator tool 96 is permitted toslide along the threads 144 of the shaft 94.

The separator tool 96 also includes a pair of arms 170, 172 that extendoutwardly from the plate 150. As shown in FIG. 3, an opening 174 isdefined between the arms 170, 172, which is sized to receive theproximal end 52 of the stem 26 and the keels 56 of the tibial tray 20,as described in greater detail below. Each of the arms 170, 172 includesa wedge 176 that is defined by a substantially planar top surface 178, asubstantially planar bottom surface 180, and a tapered surface 182extending between the surfaces 178, 180. Each of the arms 170, 172 has atip 184 formed by the intersection of the top surface 178 and thetapered surface 182.

As described above, the instrument 90 also includes an actuation collar98 that is operable to move the separator tool 96 along the shaft 94. Asshown in FIGS. 3 and 4, the collar 98 includes a housing 190 and a shank192 extending outwardly from the housing 190. The housing 190 has asurface 194 that is configured to engage the side surface 156 of theseparator tool 96. An opening (not shown) is defined in the surface 194of the housing 190, and a cylindrical inner wall 198 extends inwardlyfrom the opening to define an aperture 200 in the housing 190.

The collar 98 has a plurality of internal threads 202 formed on theinner wall 198 of the housing 190, and the internal threads 202correspond to the external threads 144 of the shaft 94. As shown in FIG.4, the internal threads 202 of the collar 98 engage the external threads144 such that rotation of the collar 98 about the longitudinal axis 140of the shaft 94 causes the collar 98 to move along the shaft 94. In theillustrative embodiment, clockwise rotation of the collar 98 advancesthe collar 98 along the shaft 94 toward the anchor 92, as indicated byarrow 204 in FIG. 4; counter-clockwise rotation of the collar 98 movesthe collar 98 away from the anchor 92, as indicated by arrow 206 in FIG.4.

When the collar 98 is rotated clockwise, the collar 98 is advanced intocontact with the separator tool 96. The surface 194 of the collar 98engages the side surface 156 of the body 152 such that continuedmovement of the collar 98 causes the separator tool 96 to move towardthe anchor 92. In that way, the collar 98 is operable to move theseparator tool 96 along the shaft 94. The collar 98 may be utilized tomove the anchor 92 between a position in which the anchor 92 is spacedapart from the opening 174 defined between the arms 170, 172 of theseparator tool 96 and, as shown in FIG. 3, another position in which theanchor 92 is positioned in the opening 174.

As described above, the collar 98 of the instrument 90 also includes ashank 192 that extends outwardly from the housing 190. The shank 192 issized and shaped to be received in a corresponding socket 210 of aT-handle 212 (see FIG. 8), which may be operated by a surgeon or otheruser to rotate the collar 98 about the longitudinal axis 140. The shank192 may also be sized to receive a socket of a power tool (not shown)such that the collar 98 may be rotated by an electric motor. It shouldalso be appreciated that the collar 98 may also be rotated by hand, and,in other embodiments, the housing 190 of the collar 98 may include agrip sized to receive a hand of a surgeon.

As shown in FIG. 4, the collar 98 of the instrument 90 has a bore 214defined in the housing 190. The bore 214 has a longitudinal axis 216that extends transverse to the longitudinal axis 140 of the shaft 94.The bore 214 is sized to receive a stabilizer rod 218 (see FIG. 7),which may be used by the surgeon to support the instrument 90 on thepatient's tibia 18.

In operation, the disassembly instrument 90 may be used during anorthopaedic surgical procedure to facilitate the removal of apreviously-implanted tibial component 14. To do so, as shown in FIGS.5-8, the surgeon may remove bone cement from between the tibial tray 20of the tibial component 14 and the proximal end 16 of the patient'stibia 18. The surgeon may utilize the instrument 90 to separate thetibial tray 20 from the sleeve 22 and remove the tibial tray 20 from thepatient's tibia 18. Thereafter, the surgeon may remove the sleeve 22from the patient's tibia 18 before preparing the patient's tibia 18 toreceive a replacement prosthetic tibial component.

As shown in FIG. 5, the tibial component 14 is implanted in the proximalend 16 of the patient's tibia 18. In the illustrative embodiment, bonecement 220 is positioned between the distal side 28 of the tibial tray20 and the proximal surface 222 of the patient's tibia 18. The surgeonmay utilize a surgical saw 224 to remove a portion of the bone cement220 and/or bone 18 from the area between the tray 20 and the surface222. In that way, a gap 226 is defined between patient's tibia 18 andthe distal side 28 of the tibial tray 20, as shown in FIG. 6.

The surgeon may utilize the disassembly instrument 90 to separate thetibial tray 20 from the sleeve 22. To do so, the surgeon inserts theengagement arm 102 of the anchor 92 into the bore 36 defined in thetibial tray 20 of the tibial component 14, as shown in FIG. 6. Whenproperly positioned, the upper body 112 of the engagement arm 102 isreceived in the proximal section 42 of the bore 36 and the lower body114 of the engagement arm 102 is received in the distal section 46. Asshown in FIG. 6, the shaft 94 extends anteriorly from the patient'stibia 18.

The separator tool 96 of the instrument 90 is initially spaced apartfrom the anchor 92 and the tibial component 14 before being advancedinto engagement with the tibial component 14. To move the separator tool96 toward the tibial component 14, the surgeon may attach a handle 212to the actuation collar 98. As shown in FIG. 6, the handle 212 has asocket 210 defined therein that is sized to receive the shank 192. Thesurgeon may rotate the handle 212 about the longitudinal axis 140 in thedirection indicated by arrow 230, thereby rotating the actuation collar98. As the collar 98 is rotated, the collar 98 is advanced into contactwith the separator tool 96. The surface 194 of the collar 98 engages theside surface 156 of the body 152 to move the separator tool 96 along theshaft 94 in the direction indicated by arrow 204. In that way, theseparator tool 96 is advanced toward the anchor 92 and the tibialcomponent 14 implanted in the patient's tibia 18. It should beappreciated that in other embodiments the surgeon may rotate the collar98 by, for example, gripping the housing 190.

The surgeon may continue to rotate the handle 212 to move the separatortool 96 posteriorly into engagement with the tibial component 14 and theproximal end 16 of the patient's tibia 18. As shown in FIG. 7, the tip184 of each of the arms 170, 172 is advanced into the gap 226 formedbetween the patient's tibia 18 and the distal side 28 of the tibial tray20 and further into the slot 84 defined between the distal side 28 ofthe tibial tray 20 and the proximal surface 72 of the sleeve 22. Thesurgeon may use the stabilizer rods 130, 218 to support the instrument90 on the patient's tibia 18.

When the tips 184 of the arms 170, 172 are positioned in the slot 84,the surgeon may apply additional force to the handle 212 to continue torotate the handle 212 about the axis 140. The surgeon may also applyadditional force using the stabilizer rod 218. In doing so, the wedges176 of the arms 170, 172 exert an upward force on the tibial tray 20, asindicated by arrow 232 in FIG. 8. As the separator tool 96 is advancedanterior to posterior, the tapered surfaces 182 of the arms 170, 172slide along the bone 18 and the proximal end 62 of the sleeve 22,thereby moving the tibial tray 20 upward while the sleeve 22 remains inposition within the patient's tibia 18. In that way, the frictional lockbetween the sleeve 22 and the tray 20 may be broken such that the tibialtray 20 may be separator from the sleeve 22.

The surgeon may continue moving the separator tool 96 posteriorly untilthe stem 26 and the keels 56 of the tibial tray 20 are positioned in theopening 174 defined between the arms 170, 172. In that position, theplanar top surface 178 of the arms 170, 172 is engaged with the distalside 28 of the tibial tray 20 and the planar bottom surface 180 of thearms 170, 172 is engaged with the proximal surface 72 of the sleeve 22.The surgeon may then manually remove the tibial tray 20 from the sleeve22 and hence from the patient's tibia 18. If the surgeon is unable tomanually remove the tibial tray 20, the surgeon may use a mallet (notshown) or other surgical tool to complete the separation of the tibialtray 20 from the sleeve 22 and the patient's tibia 18.

Once the tibial tray 20 is removed, the surgeon may the remove thesleeve 22 by using a separate removal tool. The surgeon may thensurgically prepare the proximal end 16 of the patient's tibia to receivea replacement tibial component.

Referring now to FIG. 9, another embodiment of a disassembly instrument(hereinafter instrument 290) is shown. Some features of the embodimentillustrated in FIG. 9 are substantially similar to those described abovein reference to the embodiment of FIGS. 1-8. Such features aredesignated in FIG. 9 with the same reference numbers as those used inFIGS. 1-8. Like the disassembly instrument described above in regard toFIGS. 1-8, the disassembly instrument 290 is configured to separate atibial tray 20 from the sleeve 22 and facilitate the removal of thetibial component 14.

The instrument 290 includes an anchor 292 configured to be secured to aplurality of tibial trays of a plurality of tibial components, asdescribed in greater detail below. The instrument 290 has a shaft 294 isremovably coupled to the anchor 292 via a locking pin 296. Theinstrument 290 also includes a separator tool 96 configured to moverelative to the anchor 292 and engage the tibial component to separatethe tibial tray from the sleeve. An actuation collar 98 is attached tothe shaft 294 and is operable to move the separator tool 96 along theshaft 294. In the illustrative embodiment, the components of theinstrument 290 are formed from a metallic material such as, for example,steel, titanium alloy, cobalt chromium alloy, and so forth. It should beappreciated that in other embodiments the components may be formed froma hard polymeric material.

The anchor 292 of the instrument 290 includes a base 300, an engagementarm 102 configured to be positioned in the bore 36 defined in the tibialtray 20, and another engagement arm 302 configured to be positioned in abore of another tibial tray (not shown). In the illustrative embodiment,the engagement arm 102 is secured to the base 100 via a connecting rod104. As shown in FIG. 9, the connecting rod 104 extends between a bottomsurface 106 of the base 100 and an upper surface 108 of the engagementarm 102. It should be appreciated that in other embodiments theengagement arm 102 may be secured directly to the base 100.

The engagement arm 102 has a longitudinal axis 110 that extends throughan upper body 112 secured to the connecting rod 104 and a lower body 114positioned below the upper body 112. In the illustrative embodiment, theupper body 112 has a frustoconical outer surface 116 shaped to match thetapered surface 38 that defines the proximal section 42 of the bore 36.When the anchor 92 is secured to the tibial tray 20, the upper body 112of the arm 102 is received in the proximal section 42 of the bore 36 ofthe tibial tray 20. Additionally, the lower body 114 of the engagementarm 102 is received in the distal section 46 of the bore 36 when theanchor 292 is secured to the tibial tray 20. Similar to the upper body112, the lower body 114 has a cylindrical outer surface 118 shaped tomatch the cylindrical surface 44 that defines the distal section 46 ofthe bore 36.

The base 300 of the anchor 292 includes a pair of side surfaces 120 thatextend upwardly from the bottom surface 106. An opening 122 is definedin each side surface 120, and an inner wall 124 extends between theopenings 122 to define a bore 126 through the base 300. The bore 126 issized to receive a stabilizer rod 130, which may be used by the surgeonto support the instrument 90 on the patient's tibia 18.

As shown in FIG. 9, the base 300 has a top surface 304 that ispositioned opposite the bottom surface 106. The engagement arm 302extends upwardly from the top surface 304. The engagement arm 302 has acylindrical body 306 and a tip 308 that are sized to be received in abore defined in a tibial tray having a configuration different from thatof the tibial tray 20. In that way, the instrument 290 may be todisassemble multiple types of tibial trays and sleeves. For example, inthe illustrative embodiment, the tibial tray 20 is a mobile bearingtibial tray configured for use with a mobile tibial bearing, and, asdescribed above, the engagement arm 102 is configured to be received inthe bore 36 defined in the tray 20. A fixed bearing tibial trayconfigured for use with a fixed tibial bearing may be implanted in thepatient's tibia, and the engagement arm 302 of the anchor 292 isconfigured to be received in a bore defined in the fixed bearing tibialtray.

The base 300 of the anchor 292 further includes another side surface 310that extends upwardly from the bottom surface 106 between the sidesurfaces 120. The side surface 310 has an opening 312 defined therein,and an inner wall 314 extends inwardly from the opening 312 to define anaperture 316 in the base 300. The aperture 316 is sized to receive theend 320 of the shaft 294.

As shown in FIG. 9, the shaft 294 has a cylindrical body 322 extendingfrom the end 320 to another end (not shown) positioned in the collar 98.The body 322 has a longitudinal axis 140 that extends orthogonal to thelongitudinal axis 110 of the engagement arm 102. The body 322 has acylindrical outer surface 142 that has a plurality of external threads144 formed thereon, and the external threads 144 engage with theinternal threads 202 of the collar 98 as described above in regard toFIGS. 1-8.

The anchor 292 of the instrument 290 is secured to the shaft 294 at ajoint 330. The joint 330 includes the locking pin 296, which extendsthrough a pair of openings 332 defined in the side surfaces 120 of thebase 300 and a through-hole 334 defined in the cylindrical body 322 ofthe shaft 294. The pin 296 is removable from the openings 332 andthrough-hole 334 such that the anchor 292 be attached and detached fromthe shaft 294. In that way, the orientation of the engagement arms 102,302 may be reversed such that the engagement arm 302 faces downwardwhile the engagement arm 102 faces upward.

In operation, the disassembly instrument 290 may be used during anorthopaedic surgical procedure to facilitate the removal of apreviously-implanted tibial component. If the tibial component includesthe mobile bearing tibial tray 20, the surgeon may secure the anchor 292to the shaft 294 in the orientation shown in FIG. 9. To do so, thesurgeon may advance the base 300 over the shaft 294 such that the end320 of the shaft 294 is positioned in aperture 316 of the base 300. Thesurgeon may then advance the pin 296 through the openings 332 defined inthe base 300 and the through-hole 334 of the shaft 294, thereby securingthe anchor 292 to the shaft 294.

If the tibial component includes a fixed bearing tibial tray, thesurgeon may reverse the orientation of the anchor 292 such that theengagement arm 302 faces downward (i.e., opposite the orientation shownin FIG. 9). The surgeon may then secure to the anchor 292 to the shaft294 in the manner described above. The surgeon may advance the base 300over the shaft 294 such that the end 320 of the shaft 294 is positionedin aperture 316 of the base 300. The surgeon may then advance the pin296 through the openings 332 defined in the base 300 and thethrough-hole 334 of the shaft 294, thereby securing the anchor 292 tothe shaft 294. When assembled in either orientation, the instrument 290may be used in a manner similar to that described above in regard toFIGS. 1-8 to remove an implanted tibial component from the patient'stibia.

While the disclosure has been illustrated and described in detail in thedrawings and foregoing description, such an illustration and descriptionis to be considered as exemplary and not restrictive in character, itbeing understood that only illustrative embodiments have been shown anddescribed and that all changes and modifications that come within thespirit of the disclosure are desired to be protected.

There are a plurality of advantages of the present disclosure arisingfrom the various features of the method, apparatus, and system describedherein. It will be noted that alternative embodiments of the method,apparatus, and system of the present disclosure may not include all ofthe features described yet still benefit from at least some of theadvantages of such features. Those of ordinary skill in the art mayreadily devise their own implementations of the method, apparatus, andsystem that incorporate one or more of the features of the presentinvention and fall within the spirit and scope of the present disclosureas defined by the appended claims.

The invention claimed is:
 1. An orthopaedic surgical instrumentcomprising: an anchor having a longitudinal axis, a shaft coupled to theanchor, the shaft having a longitudinal axis extending orthogonal to thelongitudinal axis of the anchor, and a separator moveably coupled to theshaft, the separator having a body secured to a pair of arms and a slotdefined between the pair of arms, wherein the shaft is positioned in abore defined in the body, and the separator is configured to moverelative to the shaft along the longitudinal axis of the shaft between(i) a first position in which the anchor is spaced apart from the slotof the separator and (ii) a second position in which the anchor isreceived in the slot defined between the pair of arms.
 2. Theorthopaedic surgical instrument of claim 1, wherein each arm of theseparator includes a top surface, a bottom surface, and a taperedsurface extending between the top surface and the bottom surface.
 3. Theorthopaedic surgical instrument of claim 1, further comprising: a collarrotatively coupled to the shaft, wherein the collar is operable to movethe separator between the first position and the second position.
 4. Theorthopaedic surgical instrument of claim 3, wherein: the shaft has aplurality of external threads formed thereon, and the bore in the bodyis defined by a substantially smooth inner surface that engages theshaft.
 5. The orthopaedic surgical instrument of claim 4, wherein: thecollar includes an opening defined in a first end thereof and an innerwall that extends inwardly from the opening, and the inner wall of thecollar has a plurality of internal threads formed thereon, the pluralityof internal threads being engaged with a number of the external threadsof the shaft.
 6. The orthopaedic surgical instrument of claim 5, whereinthe first end of the collar is engaged with the body such that rotationof the collar in a first direction causes the separator to advancebetween the first position and the second position.
 7. The orthopaedicsurgical instrument of claim 6, wherein the body is positioned betweenthe anchor and the collar.
 8. The orthopaedic surgical instrument ofclaim 6, further comprising: a handle configured to rotate the collarabout the longitudinal axis of the shaft to advance the separatorbetween the first position and the second position, wherein (i) thehandle has a socket defined therein, and (ii) the collar has a shanksized to be positioned in the socket defined in the handle.
 9. Theorthopaedic surgical instrument of claim 1, wherein the anchor includesa cylindrical shaft extending along the longitudinal axis of the anchor,the cylindrical shaft being sized and shaped to be positioned in a boredefined in a tibial tray.
 10. The orthopaedic surgical instrument ofclaim 1, further comprising a stabilizer including a rod received in abore defined in the anchor.
 11. An orthopaedic surgical instrumentcomprising: an anchor including a frustoconical first body and acylindrical second body extending downwardly from the frustoconicalfirst body, a shaft extending from a first longitudinal end secured tothe anchor to a second longitudinal end, the shaft having anexternally-threaded outer surface and a longitudinal axis extendingthrough the first longitudinal end and the second longitudinal end, ahousing having an internally-threaded inner surface engaged with theexternally-threaded outer surface of the shaft, the housing beingconfigured to rotate about the longitudinal axis of the shaft, and aseparator including (i) a mounting body positioned between the anchorand the housing and (ii) a pair of arms having a slot definedtherebetween, wherein the housing is engaged with the mounting body suchthat rotation of the housing about the longitudinal axis causes theseparator to move between (i) a first position in which the anchor isspaced apart from the slot of the separator and (ii) a second positionin which the anchor is received in the slot defined between the pair ofarms, and wherein the mounting body of the separator is moveably coupledto the shaft, and rotation of the housing about the longitudinal axiscauses the mounting body of the separator to move along the shaftbetween the first position and the second position.
 12. The orthopaedicsurgical instrument of claim 11, wherein each arm of the separatorincludes a tapered surface.
 13. The orthopaedic surgical instrument ofclaim 11, wherein the anchor includes a base secured to the firstlongitudinal end of the shaft, and the first body is secured to a lowerend of the base.
 14. The orthopaedic surgical instrument of claim 11,wherein the pair of arms of the separator are offset from and positionedbelow the longitudinal axis of the shaft.
 15. An orthopaedic surgicalinstrument comprising: an anchor having a longitudinal axis, a shaftextending from a first longitudinal end that is coupled to the anchor toa second longitudinal end, the shaft having a longitudinal axis thatextends through the first longitudinal end and the second longitudinalend orthogonal to the longitudinal axis of the anchor, and a separatorcoupled to the shaft, the separator having a pair of arms and a slotdefined therebetween, wherein the separator is configured to move alongthe longitudinal axis of the shaft between (i) a first position in whichthe anchor is spaced apart from the slot of the separator and (ii) asecond position in which the anchor is received in the slot definedbetween the pair of arms, and wherein the pair of arms of the separatorare offset from and positioned below the longitudinal axis of the shaft.16. The orthopaedic surgical instrument of claim 15, wherein the anchorincludes a base secured to the first longitudinal end of the shaft, anda body extending downwardly from the base.
 17. The orthopaedic surgicalinstrument of claim 16, wherein the body of the anchor includes afrustoconical first body attached to the base and a cylindrical secondbody extending downwardly from the frustoconical first body.